Technical Field
The disclosure is related to the display technology field, and more particular to a COA type liquid crystal display panel and method for manufacturing the same.
Related Art
With the development of display technology, liquid crystal display (LCD) and other flat panel display devices are widely used in mobile phones, televisions, personal digital assistants, digital cameras, notebook computers, desktop computers and other consumer electronic products because of its high-definition, wide power, thin body and broad applications, and etc., which, has become the mainstream among the display devices.
Most of the existing LCD monitors on the market are backlight type LCD display comprising a liquid crystal display panel and a backlight module. Generally the liquid crystal display panel is composed of a color filter (CF) substrate, a thin film transistor (TFT) array substrate, and a liquid crystal layer between the two substrates. The operation principle is that the rotation of the liquid crystal molecules is controlled by applying a driving voltage to the two substrate to reflect the light from the backlight module to generate an image.
In order to improve the aperture ratio of the liquid crystal display panel and reduce the parasitic capacitance effects, during the manufacturing process of the liquid crystal display panel, the color films are integrated in one side of the TFT array substrate, which is so-called COA (Color Filter On Array) technology.
The conventional liquid crystal display panel pixel generally comprises red (R) sub-pixel, green (G) sub-pixel, and blue (B) sub-pixel. The corresponding color film layer comprises red, green, and blue photoresist. However, the transmittance and the light mixing efficiency are relatively low and the power consumption is larger. In order to improve the brightness of the LCD panel and reduce energy consumption, a white sub-pixel W is added on the basis of red sub-pixel, green sub-pixel, and blue sub-pixel. The corresponding color film layer is added with a white photoresist.
Combining the RGBW technology with the COA technology, the TFT array substrate having the RGBW photoresists formed on one side thereof is smoother. The photo spacer (PS) may be formed on one side of the TFT array substrate to reduce the light leakage and the probability of occurrence of uneven brightness. In the meanwhile, the requirement for the alignment between the upper substrate and the lower substrate is reduced.
However, the photo spacer formed on one side of the TFT array substrate requires an additional photoetching process individually such that the production time for the TFT array substrate is longer and the production efficiency is lower.
Refer to FIG. 1, which is the schematic sectional view of the COA type liquid crystal display panel of the prior art. The manufacturing process of the TFT array substrate comprises the steps of sequentially forming a TFT layer 200, a photoresist layer 200 (including red photoresist R, green photoresist G, blue photoresist B, and white photoresist W), a protection layer 400, the pixel electrode layer 500 and the photo spacer layer 600 on the lower substrate 100. The photo spacer layer 600 comprises a higher primary photo spacer and a lower photo spacer. The manufacturing process requires more time due to an additional photoetching process for the photo spacer layer 600, and thus the production efficiency is lower.